Semiconductor device

ABSTRACT

A semiconductor device is provided. The semiconductor device includes a stack structure disposed on a lower structure; an insulating structure disposed on the stack structure; and a vertical structure extending in a direction perpendicular to an upper surface of the lower structure and having side surfaces opposing the stack structure and the insulating structure. The stack structure includes interlayer insulating layers and gate layers, alternately stacked, and the insulating structure includes a lower insulating layer, an intermediate insulating layer on the lower insulating layer, and an upper insulating layer on the intermediate insulating layer.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims benefit of priority to Korean Patent ApplicationNo. 10-2019-0037916 filed on Apr. 1, 2019 in the Korean IntellectualProperty Office, the disclosure of which is hereby incorporated byreference herein in its entirety.

BACKGROUND

Example embodiments of the present application relate to a semiconductordevice, and more particularly to a three-dimensional semiconductordevice.

Demand for improving integration density of a semiconductor device hasincreased, to improve price competitiveness of electronic products. Toimprove integration density of a semiconductor device, a semiconductordevice in which memory cells are arranged three-dimensionally has beensuggested instead of a semiconductor device including memory cellsarranged two-dimensionally.

SUMMARY

An example embodiment of the present application is to provide asemiconductor device having improved integration density.

Provided herein is a semiconductor device, including: a stack structure;a lower structure, wherein the stack structure is disposed on the lowerstructure; an insulating structure disposed on the stack structure; anda vertical structure extending in a direction perpendicular to an uppersurface of the lower structure, wherein the vertical structure comprisesside surfaces opposing the stack structure and opposing the insulatingstructure, wherein at least a portion of the stack structure includesinterlayer insulating layers and gate layers, wherein the interlayerinsulating layers and gate layers are alternately stacked, wherein theinsulating structure includes a lower insulating layer, an intermediateinsulating layer, and an upper insulating layer, wherein theintermediate insulating layer is disposed on the lower insulating layer,wherein the upper insulating layer is disposed on the intermediateinsulating layer, and wherein the intermediate insulating layer exhibitsetch selectivity.

In some embodiments of the semiconductor device a material of theintermediate insulating layer is different from a material of the lowerinsulating layer and a material of the upper insulating layer, and theintermediate insulating layer comprises a dopant, wherein the dopantincludes a group-5 element of the periodic table, and wherein theintermediate insulating layer exhibits the etch selectivity with respectto the upper insulating layer.

Also provided, in some embodiments is an alternative semiconductordevice, including: a stack structure; a lower structure, wherein thestack structure is disposed on the lower structure; an insulatingstructure disposed on the stack structure; a vertical structureextending in a direction perpendicular to an upper surface of the lowerstructure, wherein the vertical structure penetrates the stack structureand penetrates the insulating structure; a capping insulating layer,wherein the capping insulating layer is disposed on the insulatingstructure and on the vertical structure; and a separation structure,wherein the separation structure extends in a direction perpendicular toan upper surface of the lower structure, and wherein the separationstructure penetrates the stack structure, penetrates the insulatingstructure, and penetrates the capping insulating layer, the insulatingstructure includes a lower insulating layer, an intermediate insulatinglayer, and an upper insulating layer, the intermediate insulating layeris disposed on the lower insulating layer, the upper insulating layer isdisposed on the intermediate insulating layer, and the intermediateinsulating layer exhibits an etch selectivity.

In some embodiments of the alternative semiconductor device, at least aportion of the stack structure includes gate layers and interlayerinsulating layers, wherein the interlayer insulating layers are disposedbetween the gate layers, a material of the interlayer insulating layersis different from a material of the lower insulating layer, a materialof the upper insulating layer, and a material of the interlayerinsulating layers, and the intermediate insulating layer comprises adopant, wherein the dopant includes a group-5 element of the periodictable, and wherein the intermediate insulating layer exhibits the etchselectivity with respect to the upper insulating layer.

Also provided in some embodiments, is yet another semiconductor device,including: a stack structure; a lower structure, wherein the stackstructure is disposed on the lower structure; an insulating structuredisposed on the stack structure; a vertical structure extending in adirection perpendicular to an upper surface of the lower structure,wherein the vertical structure penetrates the stack structure andpenetrates the insulating structure; a capping insulating layer, whereinthe capping insulating layer is disposed on the insulating structure andon the vertical structure; and contact plugs, wherein the contact plugspenetrate the capping insulating layer and penetrate the insulatingstructure, the insulating structure includes a lower insulating layer,an intermediate insulating layer, and an upper insulating layer, theintermediate insulating layer is disposed on the lower insulating layer,wherein the upper insulating layer is disposed on the intermediateinsulating layer, and the intermediate insulating layer exhibits an etchselectivity.

BRIEF DESCRIPTION OF DRAWINGS

The above and other aspects, features, and advantages of the presentapplication will be more clearly understood from the following detaileddescription, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a block diagram illustrating a semiconductor device accordingto an example embodiment of the present application;

FIG. 2 is a cross-sectional diagram illustrating an example of asemiconductor device according to an example embodiment of the presentapplication;

FIG. 3 is a cross-sectional diagram illustrating a modified example of asemiconductor device according to an example embodiment of the presentapplication;

FIG. 4 is a cross-sectional diagram illustrating an example of asemiconductor device according to an example embodiment of the presentapplication;

FIG. 5 is a cross-sectional diagram illustrating a modified example of asemiconductor device according to an example embodiment of the presentapplication;

FIG. 6 is a perspective diagram illustrating an example of a portion ofa semiconductor device according to an example embodiment of the presentapplication;

FIG. 7 is a cross-sectional diagram illustrating an example of asemiconductor device and a graph illustrating an example of a dopingprofile of a portion of the semiconductor device according to an exampleembodiment of the present application;

FIG. 8 is an enlarged diagram illustrating an example of a portion of asemiconductor device according to an example embodiment of the presentapplication;

FIG. 9 is a cross-sectional diagram illustrating a modified example of asemiconductor device and a graph illustrating an example of a dopingprofile of a portion of the cross-sectional diagram according to anexample embodiment of the present application;

FIG. 10 is a cross-sectional diagram illustrating a modified example ofa semiconductor device and a graph illustrating an example of a dopingprofile of a portion of the cross-sectional diagram according to anexample embodiment of the present application;

FIG. 11 is a cross-sectional diagram illustrating a modified example ofa semiconductor device and a graph illustrating an example of a dopingprofile of a portion of the cross-sectional diagram according to anexample embodiment of the present application;

FIGS. 12A to 12F are cross-sectional diagrams illustrating variousmodified examples of portions of a semiconductor device according to anexample embodiment of the present application;

FIG. 13 is a plan diagram illustrating a semiconductor device accordingto an example embodiment of the present application;

FIGS. 14A to 14D are cross-sectional diagrams illustrating an example ofa semiconductor device;

FIG. 15 is a cross-sectional diagram illustrating a modified example ofa semiconductor device according to an example embodiment of the presentapplication;

FIG. 16 is a cross-sectional diagram illustrating a modified example ofa semiconductor device according to an example embodiment of the presentapplication;

FIG. 17 is a cross-sectional diagram illustrating a modified example ofa semiconductor device according to an example embodiment of the presentapplication;

FIG. 18A is a perspective diagram illustrating a modified example of asemiconductor device according to an example embodiment of the presentapplication;

FIG. 18B is a cross-sectional diagram illustrating a modified example ofa semiconductor device according to an example embodiment of the presentapplication;

FIG. 19 is a cross-sectional diagram illustrating a modified example ofa semiconductor device according to an example embodiment of the presentapplication;

FIGS. 20A to 26B are cross-sectional diagrams illustrating a method ofmanufacturing a semiconductor device according to an example embodimentof the present application;

FIG. 27 is a cross-sectional diagram illustrating a modified example ofa method of manufacturing a semiconductor device according to an exampleembodiment of the present application;

FIGS. 28 and 29 are cross-sectional diagrams illustrating a modifiedexample of a method of manufacturing a semiconductor device according toan example embodiment of the present application; and

FIG. 30 is a cross-sectional diagram illustrating a modified example ofa method of manufacturing a semiconductor device according to an exampleembodiment of the present application.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present application will be described asfollows with reference to the accompanying drawings.

An example of a semiconductor device will be described with reference toFIG. 1. FIG. 1 is a block diagram illustrating a semiconductor deviceaccording to an example embodiment.

Referring to FIG. 1, a semiconductor device 10 may include a memory cellarray region 20 in which a cell string S including an upper transistorUT controlled by a string selection line SSL, a lower transistor LTcontrolled by a ground selection line GSL, and memory cells MC disposedbetween the upper transistor UT and the lower transistor LT andcontrolled by word lines WL is disposed, and a peripheral circuit region40 in which a peripheral circuit used for storing information in thememory cells MC or for reading out information stored in the memorycells MC, such as a row decoder 42, a page buffer 44, an input andoutput buffer 45, a control logic 46, a voltage generator 47, and thelike, are disposed.

An example of a semiconductor device will be described with reference toFIG. 2. FIG. 2 is a cross-sectional diagram illustrating an example of asemiconductor device according to an example embodiment.

Referring to FIG. 2, in an example embodiment, a semiconductor device 10a may include a memory cell array region 20 and a peripheral circuitregion 40 a disposed adjacent to the memory cell array region 20. Theperipheral circuit region 40 a may include peripheral transistors PTincluded in a peripheral circuit. The peripheral transistors PT mayinclude a peripheral gate PG and a peripheral source/drain PSD.

In an example, the semiconductor device 10 a may include a connectionregion 25 adjacent to the memory cell array region 20. The connectionregion 25 may be referred to as “contact region” or “extension region.”

In an example, the semiconductor device 10 a may include a lowerstructure 50 a, a stack structure 65 disposed on the lower structure 50a, and an insulating structure 24 disposed on the lower structure 50 aand covering the stack structure 65. In an example embodiment, the lowerstructure 50 a may be a semiconductor substrate. The memory cell arrayregion 20 and the peripheral circuit region 40 a may be disposed on thelower structure 50 a. The stack structure 65 may be disposed in thememory cell array region 20 and may extend into the connection region25.

In the example embodiment, the stack structure 65 may include a firstregion 65 t and a second region 65 s extending from the first region 65t and having a staircase form in the connection region 25. The secondregion 65 s may have a staircase form descending from an upper surfaceof the first region 65 t. The second region 65 s may be disposed in theconnection region 25.

In the example embodiment, the staircase form may include a formgradually descending with a certain height difference between steps, andmay also include different types of staircase forms. Hereinafter, thefirst region 65 t of the stack structure 65 may be referred to as a“stack region,” and the second region 65 s of the stack structure 65 maybe referred to as a “staircase region.”

The insulating structure 24 may include a lower insulating layer 15, anintermediate insulating layer 18 disposed on the lower insulating layer15, and an upper insulating layer 21 disposed on the intermediateinsulating layer 18.

A material of the intermediate insulating layer 18 may be different froma material of the lower insulating layer 15 and a material of the upperinsulating layer 21. The intermediate insulating layer 18 may be formedof a material having etch selectivity different from etch selectivity ofa material of the lower insulating layer 15 and etch selectivity of amaterial of the upper insulating layer 21.

In the example embodiment, the semiconductor device 10 a may includevertical structures VS disposed on the lower structure 50 a andpenetrating the second region 65 s and the insulating structure 24. Thevertical structures VS may have side surfaces facing the stack structure65 and the insulating structure 24. The vertical structures VS may bedisposed in the memory cell array region 20, and may penetrate the stackregion 65 t of the stack structure 65 and the insulating structure 24disposed on the stack region 65 t.

In an example embodiment, the vertical structures VS may have uppersurfaces substantially coplanar with an upper surface of the insulatingstructure 24. The upper surfaces of the vertical structures VS and theupper surface of the insulating structure 24 may be positioned onsubstantially the same level.

The peripheral circuit region 40 a may be disposed adjacent to thememory cell array region 20, but an example embodiment thereof is notlimited thereto. In the description below, a modified example of theperipheral circuit region 40 a will be described with reference to FIG.3. FIG. 3 is a cross-sectional diagram illustrating a modified exampleof a semiconductor device according to an example embodiment.

In the modified example, referring to FIG. 3, a semiconductor device 10b may include the memory cell array region 20 and the connection region25, and a peripheral circuit region 40 b disposed below the memory cellarray region 20 and the connection region 25 as in the aforementionedexample embodiment described with reference to FIG. 2.

In the example embodiment, the semiconductor device 10 b may include alower structure 50 b. The lower structure 50 b may include a firstsubstrate 5 and the peripheral circuit region 40 b disposed on the firstsubstrate 5. The first substrate 5 may be a semiconductor substrate. Theperipheral circuit region 40 b may include peripheral transistors PTincluding a peripheral gate PG and a peripheral source/drain PSDincluded in a peripheral circuit, and a peripheral insulating layer 41covering the peripheral transistors PT.

In the example embodiment, the lower structure 50 b may further includea second substrate 52 disposed on the peripheral circuit region 40 b,and an intermediate insulating layer 54 disposed on side surfaces of thesecond substrate 52. The second substrate 52 may include a semiconductormaterial (e.g., polysilicon, and the like) and/or a conductive material(e.g., TiN, tungsten, or the like).

In an example embodiment, the semiconductor device 10 b may include thestack structure 65, the insulating structure 24, and the verticalstructures VS as in the aforementioned example described with referenceto FIG. 2. An example of the insulating structure 24 described withreference to FIGS. 2 and 3 will be described with reference to FIG. 4.FIG. 4 is a cross-sectional diagram illustrating an example of asemiconductor device according to an example embodiment.

In an example embodiment, referring to FIG. 4, the stack structure 65may include the stack region 65 t and the staircase region 65 s, and theinsulating structure 24 disposed on the stack structure 65 may includethe lower insulating layer 15, the intermediate insulating layer 18, andthe upper insulating layer 21 stacked in order, as in the exampleembodiments described with reference to FIGS. 2 and 3.

In the example embodiment, the lower insulating layer 15 may include afirst lower insulating layer 15 a and a second lower insulating layer 15b. The first lower insulating layer 15 a may be disposed on the stackregion 65 t of the stack structure 65, and the second lower insulatinglayer 15 b may be disposed on the staircase region 65 s of the stackstructure 65.

In the example embodiment, the first lower insulating layer 15 a mayhave an upper surface coplanar with an upper surface of the second lowerinsulating layer 15 b.

In the example embodiment, the first lower insulating layer 15 a mayhave a width substantially the same as a width of an upper surface ofthe stack region 65 t. The first lower insulating layer 15 a may beself-aligned with the stack region 65 t.

In the example embodiment, the intermediate insulating layer 18 may bein contact with the first and second lower insulating layers 15 a and 15b.

The vertical structures VS described with reference to FIGS. 2 and 3 maypenetrate through the stack region 65 t, the first lower insulatinglayer 15 a, the intermediate insulating layer 18, and the upperinsulating layer 21.

In the description below, modified examples of the second lowerinsulating layer 15 b and the intermediate insulating layer 18 of theinsulating structure 24 will be described with reference to FIG. 5. FIG.5 is a cross-sectional diagram illustrating a modified example of asemiconductor device according to an example embodiment.

In the modified example embodiment, referring to FIG. 5, a first lowerinsulating layer 15 a and an intermediate insulating layer 18′ stackedin order may be disposed on the stack region 65 t of the stack region 65t. A second lower insulating layer 15 b′ may be disposed on thestaircase region 65 s of the stack structure 65 as described in theaforementioned example embodiment.

In the example embodiment, the first lower insulating layer 15 a and theintermediate insulating layer 18′ may have substantially the same width.

The upper insulating layer 21 may be disposed on the intermediateinsulating layer 18′ and the second lower insulating layer 15 b′.Accordingly, the lower insulating layer 15 including the first andsecond lower insulating layers 15 a and 15 b′, the intermediateinsulating layer 18′, and the insulating structure 24 including theupper insulating layer 21 may be disposed on the stack structure 65.

In the example embodiment, the second lower insulating layer 15 b′ mayhave an upper surface coplanar with an upper surface of the intermediateinsulating layer 18′.

The upper insulating layer 21 may be in contact with the second lowerinsulating layer 15 b′ and the intermediate insulating layer 18′.

In the description below, example embodiments of the stack structure 65,the insulating structure 124, and the vertical structure VS disposed inthe memory cell array region 20 described in the aforementioned exampleembodiment will be described with reference to FIG. 6. FIG. 6 is aperspective diagram illustrating an example of a semiconductor deviceaccording to an example embodiment.

Referring to FIG. 6, a stack structure 165, an insulating structure 124,and a vertical structure VS may be disposed on a lower structure 50. Thelower structure 50 may be the lower structure 50 a (in FIG. 2)illustrated in the example in FIG. 2, or may be the lower structure 50 b(in FIG. 3) illustrated in the example in FIG. 3.

The stack structure 165 may include interlayer insulating layers 102 andgate layers 162, alternately stacked. The interlayer insulating layers102 may be formed of an insulating material such as a silicon oxide, andthe like.

The gate layers 162 may include one or a plurality of lower gate layers162L, a plurality of interlayer gate layers 162M disposed on one or aplurality of the lower gate layers 162L, and one or a plurality of uppergate layers 162U disposed on the plurality of interlayer gate layers162M.

In the example embodiment, as for one or a plurality of the lower gatelayers 162L, a plurality of lower gate layers 162L may be disposed. Forexample, the plurality of lower gate layers 162L may include a firstlower gate layer 162L1, a second lower gate layer 162L2, and a thirdlower gate layer 162L3 disposed in order in a direction perpendicular toan upper surface of the lower structure 50 from an upper surface of thelower structure 50.

In the example embodiment, as for one or a plurality of the upper gatelayers 162U, a plurality of the upper gate layers 162U may be disposed.For example, the plurality of upper gate layers 162U may include a firstupper gate layer 162U1, a second upper gate layer 162U2, a third uppergate layer 162U3, and a fourth upper gate layer 162U4 disposed in orderin a direction of the lower structure 50 from an upper surface of thestack structure 165.

The insulating structure 124 may include a lower insulating layer 115,an intermediate insulating layer 118, and an upper insulating layer 121stacked in order. The insulating structure 124 may be substantially thesame as the insulating structure 24 (in FIGS. 4 and 5) disposed in thememory cell array region 20 illustrated in the examples illustrated inFIGS. 4 and 5. For example, the lower insulating layer 115, theintermediate insulating layer 118, and the upper insulating layer 121 ofthe insulating structure 124 may correspond to the first lowerinsulating layer 15 a (in FIGS. 4 and 5), and the intermediateinsulating layer 18 and 18′ (in FIGS. 4 and 5), and the upper insulatinglayer 21 (in FIGS. 4 and 5) of the insulating structure 24 (in FIGS. 4and 5), respectively, described with reference to FIGS. 4 and 5. Thus,as described above, the intermediate insulating layer 118 may be formedof a material different from a material of the lower insulating layer115 and a material of the upper insulating layer 121.

A hole 130 penetrating the stack structure 165 and the insulatingstructure 124 in order may be disposed. The vertical structure VS may bedisposed in the hole 130. The vertical structure VS may extend in adirection perpendicular to an upper surface of the lower structure 50and may penetrate through the stack structure 165 and the insulatingstructure 124 in order. The vertical structure VS may have side surfacesopposing side surface of the stack structure 165 and side surfaces ofthe insulating structure 124. The vertical structure VS may have anupper surface substantially coplanar with an upper surface of the stackstructure 165.

The vertical structure VS may include a semiconductor pattern 140. Thesemiconductor pattern 140 may include a pad portion 140P positioned on ahigher level than the stack structure 165, and a liner portion 140Lextending in a direction of the lower structure 50 from an edge regionof the pad portion 140P.

The vertical structure VS may include a channel region 140Lc and dopedregions 140Ld and 140Pd. The channel region 140Lc may be formed in theliner portion 140L of the semiconductor pattern 140. The doped regions140Ld and 140Pd may include the first doped region 140Pd formed in thepad portion 140P of the semiconductor pattern 140, and the second dopedregion 140Ld extending into the liner portion 140L from the first dopedregion 140Pd and formed in the liner portion 140L.

In the example embodiment, the insulating structure 124 may oppose thedoped regions 140Ld and 140Pd. A lower surface of the insulatingstructure 124 may be disposed on a higher level than a contact region140J.

The vertical structure VS may further include a core pattern 142, and adielectric structure 138 surrounding an external side surface of thesemiconductor pattern 140. The semiconductor pattern 140 may surroundside surfaces of the core pattern 142 and may cover an upper surface ofthe core pattern 142. The semiconductor pattern 140 may surround sidesurfaces of the core pattern 142 and may extend to a region between alower surface of the core pattern 142 and the lower structure 50. Thecore pattern 142 may be formed of an insulating material, a siliconoxide, for example. The liner portion 140L of the semiconductor pattern140 may be disposed to surround side surface of the core pattern 142,and the pad portion 140P of the semiconductor pattern 140 may bedisposed on the core pattern 142.

In the description below, various examples of the stack structure 165,the insulating structure 124, and the vertical structure VS will bedescribed with reference to FIGS. 7, 8, 9, 10, and 11. FIG. 7 is across-sectional diagram illustrating an example of a semiconductordevice and a graph illustrating an example of a doping profile of aportion of the cross-sectional diagram according to an exampleembodiment. FIG. 8 is an enlarged diagram illustrating a portion marked“A” illustrated in FIG. 7. FIG. 9 is a cross-sectional diagramillustrating a modified example of a semiconductor device and a graphillustrating an example of a doping profile of a portion of thecross-sectional diagram according to an example embodiment. FIG. 10 is across-sectional diagram illustrating another modified example of asemiconductor device and a graph illustrating an example of a dopingprofile of a portion of the cross-sectional diagram according to anexample embodiment. FIG. 11 is a cross-sectional diagram illustratinganother modified example of a semiconductor device and a graphillustrating an example of a doping profile of a portion of thecross-sectional diagram according to an example embodiment. Thecross-sectional diagram in FIG. 7 may be the cross-sectional surfacefrom portions of the plurality of interlayer gate layers 162M describedwith reference to FIG. 6 to an upper surface of the insulating structure124 described with reference to FIG. 6. In the graphs representingdoping profiles of FIGS. 7, 9, 10, and 11, a “C” axis may representdoping concentration, and a “D” axis may represent a depth taken in adirection of the stack structure 165 from an upper surface of theinsulating structure 124.

Examples of the stack structure 165, the insulating structure 124, andthe vertical structure VS will be described with reference to FIG. 7.

Referring to FIG. 7, the stack structure 165, the insulating structure124, and the vertical structure VS as in the example embodimentdescribed with reference to FIG. 6 may be disposed. The stack structure165 may include the gate layers 162 as described above. Each of the gatelayers 162 may include a first material layer 158 and a second materiallayer 160. The first material layer 158 may cover an upper surface and alower surface of the second material layer 160, and may extend to aregion between a side surface of the second material layer 160 and aside surface of the vertical structure VS.

In the example embodiment, the first material layer 158 may be formed ofa dielectric material such as an aluminum oxide, and the like, and thesecond material layer 160 may be formed of a conductive materialincluding one of or two or more of a doped silicon, a metal nitride(e.g., TiN, and the like), and a metal (e.g., W, and the like).

In another example embodiment, the first material layer 158 may beformed of a conductive material such as a metal nitride (e.g., TiN, andthe like), and the like, and the second material layer 160 may be formedof a conductive material such as a metal (e.g., W, and the like), andthe like.

As described with reference to FIG. 6, the insulating structure 124 mayinclude the lower insulating layer 115, the intermediate insulatinglayer 118, and the upper insulating layer 121 staked in order, and thevertical structure VS may include the channel region 140Lc and the dopedregions 140Ld and 140Pd formed in the semiconductor pattern 140. Thedoped regions 140Ld and 140Pd may include the first doped region 140Pdformed in the pad portion 140P of the semiconductor pattern 140, and thesecond doped region 140Ld formed in the liner portion 140L of thesemiconductor pattern 140.

In the example embodiment, a contact region 140J between the seconddoped region 140Ld and the channel region 140Lc may be disposed on alower level than an upper surface of the first upper gate layer 162U1positioned on the highest level among the gate layers 162. For example,the contact region 140J may be positioned on a level between an uppersurface of the first upper gate layer 162U1 and a lower surface of thefirst upper gate layer 162U1.

The doped regions 140Ld and 140Pd and the insulating structure 124 mayinclude a first element implanted from an upper surface 140S of thesemiconductor pattern 140 and an upper surface 124S of the insulatingstructure 124 through an ion implantation process.

In the example embodiment, the first element may be doped to haveGaussian distribution or distribution similar to Gaussian distributionin the insulating structure 124.

In the example embodiment, a doping profile of the first element mayhave the maximum concentration at a first depth Rp from the uppersurface 140S of the semiconductor pattern 140 and the upper surface 124Sof the insulating structure 124 in the insulating structure 124. Theupper surface 140S of the semiconductor pattern 140 and the uppersurface 124S of the insulating structure 124 may be coplanar with eachother. The first depth Rp may be positioned between an upper surface anda lower surface of the intermediate insulating layer 118. Thus, thefirst element in the insulating structure 124 may have the maximumconcentration in the intermediate insulating layer 118. Concentration ofthe first element in the insulating structure 124 may be higher in theintermediate insulating layer 118 than in the lower and upper insultinglayers 115 and 121.

In the example embodiment, the first element may be a group-5 element(e.g., phosphorus (P), arsenic (As), or the like) in the periodic table.Accordingly, the doped regions 140Ld and 140Pd may have N-typeconductivity.

In the example embodiment, the insulating structure 124 may besubstantially the same as the insulating structure 24 (in FIGS. 4 and 5)disposed in the memory cell array region 20 described with reference toFIGS. 4 and 5, and the insulating structure 24 (in FIGS. 4 and 5) maythus include the first element, and doping concentration of the firstelement of the insulating structure 24 (in FIGS. 4 and 5) may be thehighest in the intermediate insulating layers 18 and 18′ (in FIGS. 4 and5, respectively) than in the first lower insulating layer 15 a (in FIGS.4 and 5) and the upper insulating layer 21 (in FIGS. 4 and 5).

In the description below, it may be understood that the intermediateinsulating layer 118 may include the first element, and that dopingconcentration of the first element in the insulating structure 124 maybe the highest in the intermediate insulating layer 118 than in thelower and upper insulating layers 115 and 121. Thus, although thedescriptions thereof is not provided, it may be understood that theinsulating structure 124 or an insulating structure corresponding to theinsulating structure 124 may have the concentration distribution of thefirst element described above.

In the example embodiment, the intermediate insulating layer 118 may bean intermediate insulating layer 118 a configured to surround a boundaryregion between the pad portion 140P and the liner portion 140L of thesemiconductor pattern 140. The intermediate insulating layer 118 a maysurround an upper surface of the core pattern 142. Thus, theintermediate insulating layer 118 a may be disposed on the same level asa portion of the pad portion 140P and a portion of the liner portion140L.

In the description below, an example of the dielectric structure 138will be described with reference to FIG. 8.

Referring to FIG. 8, the dielectric structure 138 may include a firstdielectric layer 132, a data storage layer 134, and a second dielectriclayer 136. The data storage layer 134 may be disposed between the firstand second dielectric layers 132 and 136. The first dielectric layer 132may be disposed between the data storage layer 134 and the gate layers162, and may extend to a region between the data storage layer 134 andthe interlayer insulating layers 102. The second dielectric layer 136may be disposed between the semiconductor pattern 140 and the datastorage layer 134.

In the example embodiment, the data storage layer 134 may be used as adata storage region of a memory cell of a NAND fresh memory device. Forexample, regions of the data storage layer 134 opposing intermediategate layers used as the word lines WL (in FIG. 1) among the interlayergate layers 162M may be “data storage regions,” and may be included inthe memory cells MC (in FIG. 1) illustrated in the example in FIG. 1.The data storage layer 134 may be formed of a material which may trapelectric charge, such as a silicon nitride, for example. The firstdielectric layer 132 may be a blocking layer, and the second dielectriclayer 136 may be a tunneling layer. The dielectric structure 138 may bereferred to as a “gate dielectric.”

In the description below, various modified examples of levels (height)of the pad portion 140P of the vertical structure VS and theintermediate insulating layer 118 of the insulating structure 124 willbe described with reference to FIGS. 9 and 10, respectively.

In the modified example, referring to FIG. 9, the intermediateinsulating layer 118 of the insulating structure 124 may be positionedon a higher level than the liner portion 140L, and may be anintermediate insulating layer 118 b surrounding a portion of the padportion 140P. A thickness of the intermediate insulating layer 118 b maybe less than a thickness of the pad portion 140P.

In another modified example, referring to FIG. 10, the intermediateinsulating layer 118 of the insulating structure 124 may be positionedon a lower level than the pad portion 140P, and may be an intermediateinsulating layer 118 c surrounding a portion of the liner portion 140L.

In the description below, a modified example of the contact region 140Jbetween the second doped region 140Ld and the channel region 140Lc willbe described with reference to FIG. 11.

In the modified example, referring to FIG. 11, a contact region 140J′between the second doped region 140Ld and the channel region 140Lc maybe positioned on a lower level than the first upper gate layer 162U1positioned on the highest level among the gate layers 162. For example,the contact region 140J′ between the second doped region 140Ld and thechannel region 140Lc may be positioned on a level between the firstupper gate layer 162U1 positioned on the highest level among the gatelayers 162 and the second upper gate layer 162U2 positioned on thesecond highest level among the gate layers 162.

Referring back to FIG. 6, in the example embodiment, a thickness 115 taof the lower insulating layer 115 may be greater than a thickness 118 taof the intermediate insulating layer 118, a thickness 121 ta of theupper insulating layer 121, a thickness 102 t of each of the interlayerinsulating layers 102, and a thickness 162 t of each of the gate layers162. The thickness 121 ta of the upper insulating layer 121 may begreater than the thickness 118 ta of the intermediate insulating layer118. The thickness 118 ta of the intermediate insulating layer 118 maybe greater than the thickness 102 t of each of the interlayer insulatinglayers 102. The thickness 118 ta of the intermediate insulating layer118 may be the same or greater than the thickness 162 t of each of thegate layers 162.

In the description below, various modified examples of thicknesses ofthe lower insulating layer 115, the intermediate insulating layer 118,and the upper insulating layer 121 of the insulating structure 124 willbe described with reference to FIGS. 12A to 12F. FIGS. 12A to 12F arecross-sectional diagrams illustrating portions of the lower insulatinglayer 115, the intermediate insulating layer 118, and the upperinsulating layer 121 of the insulating structure 124, the first andsecond upper gate layers 162U1 and 162U2 of the stack structure 165, andthe interlayer insulating layer 102 between the first and second uppergate layers 162U1 and 162U2.

In the modified example, referring to FIG. 12A, a thickness 115 tb ofthe lower insulating layer 115, a thickness 118 tb of the intermediateinsulating layer 118, and a thickness 121 tb of the upper insulatinglayer 121 may be substantially the same. The thickness 115 tb of thelower insulating layer 115, the thickness 118 tb of the intermediateinsulating layer 118, and the thickness 121 tb of the upper insulatinglayer 121 may be greater than a thickness 162 t of each of the gatelayers 162 and a thickness 102 t of each of the interlayer insulatinglayers 102. In the example embodiment, the thickness 162 t of each ofthe gate layers 162 may be greater than the thickness 102 t of each ofthe interlayer insulating layers 102.

In another modified example, referring to FIG. 12B, a thickness 115 tcof the lower insulating layer 115 may be less than a thickness 118 tc ofthe intermediate insulating layer 118, and a thickness 121 tc of theupper insulating layer 121. The thickness 118 tc of the intermediateinsulating layer 118 may be substantially the same as the thickness 121tc of the upper insulating layer 121.

In another modified example embodiment, referring to FIG. 12C, athickness 118 td of the intermediate insulating layer 118 may be greaterthan a thickness 115 tb of the lower insulating layer 115 and athickness 12 ltb of the upper insulating layer 121.

In another modified example embodiment, referring to FIG. 12D, athickness 121 te of the upper insulating layer 121 may be greater than athickness 118 te of the intermediate insulating layer 118 and athickness 115 te of the lower insulating layer 115. The thickness 115 teof the lower insulating layer 115 may be greater than the thickness 118te of the intermediate insulating layer 118.

In another modified example, referring to FIG. 12E, a thickness 121 tfof the upper insulating layer 121 and a thickness 118 tf of theintermediate insulating layer 118 may be substantially the same, and athickness 115 tf of the lower insulating layer 115 may be greater thanthe thickness 121 tf of the upper insulating layer 121 and the thickness118 tf of the intermediate insulating layer 118.

In another modified example, referring to FIG. 12F, a thickness 121 tgof the upper insulating layer 121 may be greater than a thickness 118 tgof the intermediate insulating layer 118 and a thickness 115 tg of thelower insulating layer 115, and a thickness 118 tg of the intermediateinsulating layer 118 and the thickness 115 tg of the lower insulatinglayer 115 may be substantially the same.

In the description below, an example of a semiconductor device will bedescribed with reference to FIGS. 13, and 14A to 14D. With respect toFIGS. 13, and 14A to 14D, FIG. 13 is a plan diagram illustrating asemiconductor device 10 c according to an example embodiment. FIG. 14Ais a cross-sectional diagram illustrating a region taken along line I-I′in FIG. 13. FIG. 14B is a cross-sectional diagram illustrating a regiontaken along line II-II′ in FIG. 13. FIG. 14C is a cross-sectionaldiagram illustrating a region taken along line III-III′ in FIG. 13. FIG.14D is a cross-sectional diagram illustrating a region taken along lineIV-IV′ in FIG. 13.

Referring to FIGS. 13, and 14A to 14D, a stack structure 165, aninsulating structure 124, and a vertical structure VS may be disposed ona lower structure 50. The lower structure 50 may be the lower structure50 a illustrated in the example embodiment in FIG. 2, or may be thelower structure 50 b illustrated in the example embodiment in FIG. 3.

The stack structure 165 may be disposed in a memory cell array region20, and may extend into a connection region 25 from the memory cellarray region 20.

The stack structure 165 may include interlayer insulating layers 102 andgate layers 162, alternately stacked. The interlayer insulating layers102 may be formed of a silicon oxide.

In the memory cell array region 20, the gate layers 162 may include oneor a plurality of the lower gate layers 162L1, 162L2, and 162L3, aplurality of the interlayer gate layers 162M, and one or a plurality ofthe upper gate layers 162U1, 162U2, 162U3, and 162U4, as in theaforementioned example embodiments described with reference to FIGS. 6to 8.

In the connection region 25, the gate layers 162 may have pad regions162P arranged in staircase form. Accordingly, the stack structure 165may have a staircase form in the connection region 25.

In the example embodiment, the vertical structure VS may extend in adirection D3 perpendicular to an upper surface of the lower structure 50and may penetrate the stack structure 165 and the insulating structure124, and may include the semiconductor pattern 140, the core pattern142, the dielectric structure 138, the channel region 140Lc, and thedoped regions 140Ld and 140Pd, illustrated in the example in FIGS. 6 to8.

The insulating structure 124 may include a lower insulating layer 115,an intermediate insulating layer 118, and an upper insulating layer 121,stacked in order. The lower insulating layer 115 may include a firstlower insulating layer 115 a and a second lower insulating layer 115 bwhich may correspond to the first lower insulating layer 15 a and thesecond lower insulating layer 15 b illustrated in the example in FIG. 4,respectively. For example, the first lower insulating layer 115 a may bedisposed on the stack structure 165 in the memory cell array region 20,and the second lower insulating layer 115 b may have an upper surfacecoplanar with an upper surface of the first lower insulating layer 115 aand may be disposed on the stack structure 165 in the connection region25.

In the example embodiment, the first lower insulating layer 115 a mayoverlap and self-aligned with the first upper gate layer 162U1, anuppermost gate layer among the gate layers 162, and the second lowerinsulating layer 115 b may have an upper surface coplanar with an uppersurface of the first lower insulating layer 115 a and may be disposed inthe stack structure 165 in the connection region 25.

In the example embodiment, the intermediate insulating layer 118 may bein contact with the first and second lower insulating layers 115 a and115 b.

In the example embodiment, an insulating pattern 127 (in FIG. 14A)penetrating the insulating structure 124 and penetrating one or aplurality of the upper gate layers 162U1, 162U2, 162U3, and 162U4.

A plurality of the vertical structures VS may be disposed. Among theplurality of the vertical structures VS, vertical structures penetratingor in contact with the insulating pattern 127 may be dummy verticalstructures VSd (in FIG. 14B), and the remaining vertical structures maybe memory cell vertical structures VS. The dummy vertical structures VSdamong the plurality of the vertical structures VS may not include thememory cells MC (in FIG. 1) illustrated in the example in FIG. 1, andthe remaining vertical structures may include the memory cells MC (inFIG. 1) illustrated in the example in FIG. 1.

A first capping insulating layer 150 and a second capping insulatinglayer 178, stacked in order, may be disposed on the insulating structure124 and the vertical structure VS. The first and second cappinginsulating layers 150 and 178 may be formed of a silicon oxide.

Separation structures 175 extending in a direction D3 perpendicular toan upper surface of the lower structure 50 and penetrating the stackstructure 165, the insulating structure 124, and the first cappinginsulating layer 150 may be disposed. Each of the separation structures175 may include a separation core pattern 173 and a spacer layer 170disposed on side surfaces of the separation core pattern 173. In anexample embodiment, the spacer layer 170 may be formed of an insulatingmaterial such as a silicon oxide, and the like, and the separation corepattern 173 may be formed of a conductive material such as doped siliconor a metal. In another example embodiment, the separation core pattern173 may be formed of an insulating material.

The separation structures 175 may include first separation structures175 a and second separation structures 175 b disposed between the firstseparation structures 175 a. The stack structure 165 may be disposedbetween the first separation structures 175 a. As illustrated in FIG.13, each of the first separation structures 175 a may have a lengthtaken in a first direction D1 greater than a length of each of thesecond separation structures 175 b taken in a first direction D1. Asillustrated in FIG. 13, portions of the second separation structures 175b may cross the memory cell array region 20 and may extend into aportion of the connection region 25, and the insulating pattern 127 maybe disposed between the second separation structure 175 b crossing thememory cell array region 20 and extending into a portion of theconnection region 25 among the second separation structures 175 b, andthe first separation structures 175 a.

Bit-line contact plugs 187 penetrating the first and second cappinginsulating layers 150 and 178 and electrically connected to the padportions 140P of the vertical structure VS may be disposed.

In the connection region 25, gate contact plugs 184 penetrating thefirst and second capping insulating layers 150 and 178 and theinsulating structure 124 and electrically connected to the pad regions162P of the gate layers 162 may be disposed. Bit lines 190 may bedisposed on the bit-line contact plugs 187, and gate connection wiringlines 192 may be disposed on the gate contact plugs 184.

In the description below, a modified example of the insulating structure124 will be described with reference to FIG. 15. FIG. 15 is across-sectional diagram illustrating a region taken along line IV-IV′ inFIG. 13.

In the modified example embodiment, referring to FIG. 15, an insulatingstructure 124 may include a lower insulating layer 115, an intermediateinsulating layer 118′, and an upper insulating layer 121. The lowerinsulating layer 115 may include a first lower insulating layer 115 aand a second lower insulating layer 115 b′ having different heights ofupper surfaces. The first lower insulating layer 115 a may be disposedon the stack structure 165 in the memory cell array region 20, and theintermediate insulating layer 118′ may be self-aligned with the firstlower insulating layer 115 a. The second lower insulating layer 115 b′may have an upper surface coplanar with an upper surface of theintermediate insulating layer 118′. The second lower insulating layer115 b′ may be disposed on the staircase region 65 s of the stackstructure 65. The upper insulating layer 121 may be in contact with thesecond lower insulating layer 115 b′ and the intermediate insulatinglayer 118′.

Referring back to FIGS. 13 and 14A to 14D, the separation structures 175may be in contact with the intermediate insulating layer 118. However,an example embodiment thereof is not limited thereto, and the separationstructures 175 may be spaced apart from the intermediate insulatinglayer 118. One or more example configurations in which the separationstructures 175 and the intermediate insulating layer 118 may be spacedapart from each other will be described with reference to FIGS. 16 and17.

FIGS. 16 and 17 are cross-sectional diagrams illustrating a region takenalong line I-I′ in FIG. 13, illustrating one or more exampleconfigurations in which the separation structures 175 and theintermediate insulating layer 118 may be spaced apart from each other.

In the modified example, referring to FIG. 16, a buffer layer 151 may bedisposed between the separation structures 175 and the intermediateinsulating layer 118. The buffer layer 151 may be disposed on the stackstructure 165. The buffer layer 151 may be disposed between theseparation structures 175 and the intermediate insulating layer 118, mayextend to a region between the separation structures 175 and the lowerinsulating layer 115, and may further extend to a region between theseparation structures 175 and the intermediate insulating layer 118.Further, the buffer layer 151 may further extend to a region between theseparation structures 175 and the first capping insulating layer 150.

The buffer layer 154 may be formed of an insulating material such as asilicon oxide or a silicon nitride, for example.

In the example embodiment, the buffer layer 151 may overlap the stackstructure 165.

The buffer layer 151 may prevent defects between the doped regions 140Ldand 140Pd of the vertical structure VS, adjacent to each other, alongwith the intermediate insulating layer 118 of the insulating structure124.

In another modified example, referring to FIG. 17, the separationstructures 175 may be disposed in separation trenches 153 penetratingthe stack structure 165, the insulating structure 124, and the firstcapping insulating layer 150. A buffer layer 154 covering upper sidewalls of the separation trenches 153 may be disposed. The buffer layer154 may be positioned on a higher level than the stack structure 165.The buffer layer 154 may be formed of an insulating material such as asilicon oxide or a silicon nitride, for example. The buffer layer 154may prevent defects between the doped regions 140Ld and 140Pd of thevertical structure VS, adjacent to each other, along with theintermediate insulating layer 118 of the insulating structure 124. Thebuffer layer 154 may be referred to as a “buffer layer.”

A modified example of a semiconductor device will be described withreference to FIGS. 18A and 18B. FIG. 18A is a perspective diagramillustrating a modified example of a semiconductor device disposed inthe memory cell array region 20 described in the aforementioned exampleembodiment. FIG. 18B is a cross-sectional diagram illustrating amodified example of a semiconductor device disposed in the memory cellarray region 20 and the connection region 25 described in theaforementioned example embodiment.

In the modified examples, referring to FIGS. 18A and 18B, a lower stackstructure 265, a lower insulating structure 224, an upper stackstructure 365, and an upper insulating structure 324 may be disposed ona lower structure 50. The lower stack structure 265, the lowerinsulating structure 224, the upper stack structure 365, and the upperinsulating structure 324 may be disposed in the memory cell array region20 (in FIG. 18B) and may extend into the connection region 25 (in FIG.18B). The lower stack structure 265 may have lower pad regions 262P (inFIG. 18B) arranged in staircase form in the connection region 25 (inFIG. 18B), and the upper stack structure 365 may have upper pad regions362P (in FIG. 18B) arranged in staircase form in the connection region25 (in FIG. 18B).

Each of the lower and upper stack structures 265 and 365 may have thesame as or similar to a structure of the stack structure 165 illustratedin the examples in FIGS. 6 and 7. For example, the lower stack structure265 may include first interlayer insulating layers 202 and first gatelayers 262, alternately stacked, and the upper stack structure 365 mayinclude second interlayer insulating layers 302 and second gate layers362, alternately stacked.

A vertical structure VS' may be disposed on the lower structure 50. Thevertical structure VS' may include a lower vertical structure VS_L andan upper vertical structure VS_U disposed on the lower verticalstructure VS_L. The lower vertical structure VS_L may penetrate thelower stack structure 265 and the lower insulating structure 224. Theupper vertical structure VS_U may penetrate the upper stack structure365 and the upper insulating structure 324. Each of the lower verticalstructure VS_L and the upper vertical structure VS_U may have astructure the same as or similar to a structure of the verticalstructure VS illustrated in the examples in FIGS. 6, 7, and 8. Forexample, the lower vertical structure VS_L may include a lower corepattern 242, a lower semiconductor pattern 240, and a lower dielectricstructure 238, and the upper vertical structure VS_U may include anupper core pattern 342, and an upper semiconductor pattern 340, and anupper dielectric structure 338. In the example embodiment, each of thelower and upper dielectric structures 238 and 338 may have substantiallythe same structure as the structure of the dielectric structure 138described with reference to FIG. 8.

The lower and upper core patterns 242 and 342 may be formed of aninsulating material (e.g., a silicon oxide, and the like). The lowersemiconductor pattern 240 may include a lower pad portion 240P disposedon the lower core pattern 242, and a lower liner portion 240L extendingin a direction of the lower structure 50 from an edge region of thelower pad portion 240P. The upper semiconductor pattern 340 may includean upper pad portion 340P disposed on the upper core pattern 342, and anupper liner portion 340L extending in a direction of the lower structure50 from an edge region of the upper pad portion 340P.

The lower semiconductor pattern 240 may further extend to a regionbetween a bottom surface of the lower core pattern 242 and the lowerstructure 50 from the lower liner portion 240L. The upper semiconductorpattern 340 may further extend to a region between a bottom surface ofthe upper core pattern 342 and the lower vertical structure VS_L fromthe upper liner portion 340L. The upper liner portion 340L of the uppersemiconductor pattern 340 may be in contact with the lower pad portion240P of the lower semiconductor pattern 240.

The lower vertical structure VS_L may include a lower channel region240Lc and lower doped regions 140Ld and 140Pd, and the upper verticalstructure VS_U may include an upper channel region 340Lc and upper dopedregions 340Ld and 340Pd.

The lower channel region 240Lc may be formed in the lower liner portion240L of the lower semiconductor pattern 240, and the lower doped regions140Ld and 140Pd may include a first lower doped region 240Pd formed inthe lower pad portion 240P of the lower semiconductor pattern 240, and asecond lower doped region 240Ld extending into the lower liner portion240L from the first lower doped region 240Pd and formed in the lowerliner portion 240L.

The upper channel region 340Lc may be formed in the upper liner portion340L of the upper semiconductor pattern 340, and the upper doped regions340Ld and 340Pd may include a first upper doped region 340Pd formed inthe upper semiconductor pattern 340 of the upper semiconductor pattern340, and a second upper doped region 340Ld extending into the upperliner portion 340L from the first upper doped region 340Pd and formed inthe upper liner portion 340L.

In the example embodiment, the upper doped regions 340Ld and 340Pd andthe lower doped regions 240Ld and 240Pd may be substantially the same asthe doped regions 140Ld and 140Pd (in FIG. 7) described with referenceto FIG. 7.

In the example embodiment, each of the lower and upper insulatingstructures 224 and 324 may have a structure the same as or similar to astructure of the insulating structure 124 (in FIGS. 6 and 7) illustratedin the examples in FIGS. 6 and 7. For example, the lower insulatingstructure 224 may include a lower insulating layer 215, an intermediateinsulating layer 218, and an upper insulating layer 221, stacked inorder, and the upper insulating structure 324 may include a lowerinsulating layer 315, an intermediate insulating layer 318, and an upperinsulating layer 321 stacked in order. In the example embodiment, thelower insulating layer 215 of the lower insulating structure 224 mayinclude a first lower insulating layer 215 a (in FIG. 18B) aligned withan uppermost gate layer 262 (in FIG. 18B) among the first gate layers262, and a second lower insulating layer 215 b covering the lower padregions 262P (in FIG. 18B).

In the example embodiment, the lower insulating layer 315 of the lowerinsulating layer 315 may include a first lower insulating layer 315 a(in FIG. 18B) aligned with an uppermost gate layer 362 (in FIG. 18B)among the second gate layers 362, and a second lower insulating layer315 b covering upper pad regions 362P (in FIG. 18B).

A first capping insulating layer 150 (in FIG. 18B) and a second cappinginsulating layer 178 (in FIG. 18B), stacked in order, may be disposed onthe upper insulating structure 324. A bit line contact plug 187 (in FIG.18B) penetrating the first and second capping insulating layers 150 and178 (in FIG. 18B) and electrically connected to the upper pad portion340P (in FIG. 18B) of the upper vertical structure VS_U of the verticalstructure VS' may be disposed. A bit line 190 (in FIG. 18B) may bedisposed on the bit line contact plug 187 (in FIG. 18B).

Gate contact plugs 184 may be disposed in the connection region 25 (inFIG. 18B). Some plugs of the gate contact plugs 184 may be disposed onthe upper pad regions 362P (in FIG. 18B), and may extend to an upperportion and may penetrate the upper insulating structure 324 (in FIG.18B) and the first and second capping insulating layers 150 and 178 (inFIG. 18B). The other plugs of the gate contact plugs 184 (in FIG. 18B)may be disposed on the lower pad regions 262P (in FIG. 18B), and mayextend to an upper portion and may penetrate the lower insulatingstructure 224 (in FIG. 18B), the upper insulating structure 324 (in FIG.18B), and the first and second capping insulating layers 150 and 178 (inFIG. 18B). Gate connection wiring lines 192 (in FIG. 18B) may bedisposed on the gate contact plugs 184 (in FIG. 18B).

The upper insulating structure 324 including the intermediate insulatinglayer 318, and the lower insulating structure 224 including theintermediate insulating layer 218 may prevent electrical shorts, currentleakage, or the like, occurring between the gate contact plugs 184.

In the description below, modified examples of the vertical structure VSand the separation structures 175 described in the aforementionedexample embodiment will be described with reference to FIG. 19. FIG. 19is a cross-sectional diagram illustrating a region taken along line I-I′along FIG. 13.

In the modified example, referring to FIGS. 13 and 19, the lowerstructure 50, the stack structure 165, the insulating structure 124, thefirst capping insulating layer 150, and the second capping insulatinglayer 178, described with reference to FIGS. 13, and 14A to 14D, may bedisposed.

A base insulating layer 405 may be disposed between the lower structure50 and the stack structure 165, and a horizontal connection pattern 410may be disposed on the base insulating layer 405.

A vertical structure VS penetrating the stack structure 165 and theinsulating structure 124 may be disposed on the lower structure 50. Thevertical structure VS may include the core pattern 142, thesemiconductor pattern 140, and the dielectric structure 138, describedwith reference to FIGS. 13, and 14A to 14D. The semiconductor pattern140 may include a liner portion 140L surrounding side surfaces of thecore pattern 142 as described in the aforementioned example embodiment.

The horizontal connection pattern 410 may be disposed below the stackstructure 165, may penetrate the dielectric structure 138, and may beconnected to the liner portion 140L. For example, the horizontalconnection pattern 410 may be in contact with the liner portion 140L. Inan example embodiment, the horizontal connection pattern 410 may includea polysilicon having N-type conductivity.

Separation structures 175 penetrating the stack structure 165, theinsulating structure 124, and the first capping insulating layer 150 maybe disposed. Each of the separation structures 175 may include aseparation core pattern 173, and a spacer layer 170 disposed on sidesurfaces of the separation core pattern 173.

Lower patterns 415 may be disposed between the separation structures 175and the lower structure 50. In an example embodiment, the lower patterns415 may be an epitaxial semiconductor layer formed by an epitaxialprocess from the lower structure 50. In another example, the lowerpatterns 415 may be formed of polysilicon. In an example embodiment, thelower patterns 415 may include silicon having N-type conductivity.

In the description below, an example of a method of manufacturing asemiconductor device will be described with reference to FIGS. 20A to26B. With respect to FIGS. 20A to 26B, FIGS. 20A, 21A, 22A, 23A, 24,25A, and 26A are cross-sectional diagrams illustrating a region takenalong line I-I′ in FIG. 13, and FIGS. 20B, 21B, 22B, 23B, 25B, and 26Bare cross-sectional diagrams illustrating a region taken long lineIV-IV′ in FIG. 13.

Referring to FIGS. 13, 20A, and 20B, a mold structure 106 includinginterlayer insulating layers 102 and mold layers 104, alternatelystacked, may be formed on a lower structure 50. The interlayerinsulating layers 102 may be formed of a silicon oxide, and the moldlayers 104 may be formed of a material having etch selectivity with theinterlayer insulating layers 102. For example, the mold layers 104 maybe formed of a material having etch selectivity with the interlayerinsulating layers 102, and the material having etch selectivity with theinterlayer insulating layers 102 may not be limited to any particularmaterial. For example, when the interlayer insulating layers 102 areformed of a silicon oxide, the mold layers 104 may be formed of amaterial having etch selectivity with a silicon oxide, such as a siliconnitride, a polysilicon, or the like.

A first lower insulating layer 115 a may be formed on the mold structure106. The first lower insulating layer 115 a may be formed of a siliconoxide.

A staircase structure may be formed by patterning the first lowerinsulating layer 115 a and the mold structure 106. Accordingly, theinterlayer insulating layers 102 and the mold layers 104 of the moldstructure 106 may be alternately stacked in the memory cell array region20, and may be formed in a staircase structure in a connection region 25adjacent to the memory cell array region 20.

Referring to FIGS. 13, 21A, and 21B, a second lower insulating layer 115b (in FIG. 21B) having an upper surface coplanar with an upper surfaceof the first lower insulating layer 115 a may be formed. For example,the forming the second lower insulating layer 115 b (in FIG. 21B) mayinclude forming an insulating layer on the lower structure 50 having thefirst lower insulating layer 115 a and the mold structure 106, andplanarizing the insulating layer until an upper surface of the firstlower insulating layer 115 a is exposed. The first and second lowerinsulating layers 115 a and 115 b may be included in a lower insulatinglayer 115.

An intermediate insulating layer 118 and an upper insulating layer 121,stacked in order, may be formed on the lower insulating layer 115. Thelower insulating layer 115, the intermediate insulating layer 118, andthe upper insulating layer 121, stacked in order, may be included in aninsulating structure 124.

In the example embodiment, the intermediate insulating layer 118 may beformed of a material the same as a material of the lower insulatinglayer 115, such as a silicon oxide, for example.

In the example embodiment, the intermediate insulating layer 118 may beformed of a material different from materials of the lower and upperinsulating layers 115 and 121 and a material of the interlayerinsulating layers 102. For example, the intermediate insulating layer118 may be formed of a material having etch selectivity different frometch selectivity of the lower and upper insulating layers 115 and 121.For example, the lower and upper insulating layers 115 and 121 and theinterlayer insulating layers 102 may be formed of a silicon oxide, andthe intermediate insulating layer 118 may be formed of a siliconnitride. In example embodiments, a material of the intermediateinsulating layer 118 may not be limited to a silicon nitride, and may bereplaced with an insulating material having etch selectivity differentfrom etch selectivity of the lower and upper insulating layers 115 and121 and the interlayer insulating layers 102.

In the example embodiment, the intermediate insulating layer 118 may beformed of a material different from a material of the mold layers 104.For example, when the mold layers 104 are formed of polysilicon orformed as amorphous carbon layers, the intermediate insulating layer 118may be formed of a silicon nitride. For example, when the mold layers104 are formed of a silicon nitride, the intermediate insulating layer118 may be formed of an insulating material different from a siliconnitride.

An insulating pattern 127 (in FIG. 21A) penetrating the insulatingstructure 124 and a portion of the mold structure 106 may be formed. Theinsulating pattern 127 (in FIG. 21A) may be formed of a silicon oxide.

Referring to FIGS. 13, 22A, and 22B, a vertical structure VS penetratingthe mold structure 106 and the insulating structure 124 may be formed onthe lower structure 50.

In the example embodiment, the forming the vertical structure VS mayinclude forming a hole 130 penetrating the mold structure 106 and theinsulating structure 124, forming a dielectric structure 138 on a sidewall of the hole 130, forming a liner portion 140L covering thedielectric structure 138 on an internal wall of the hole 130, forming acore pattern 142 partially filling the hole 130 in which the linerportion 140L is formed, and forming a pad portion 140P connected to theliner portion 140L on the core pattern 142. The liner portion 140L andthe pad portion 140P may be formed as a semiconductor pattern 140. Thesemiconductor pattern 140 may be formed of polysilicon.

Referring to FIGS. 13, 23A, and 23A, an ion implantation process 148 maybe performed. Through the ion implantation process 148, the pad portion140P of the semiconductor pattern 140 may be formed as a first dopedregion 140Pd, and a portion of the liner portion 140L of thesemiconductor pattern 140 may be formed as a second doped region 140Ld.

In an example embodiment, a portion of the second doped region 140Ld mayoppose side surfaces of at least an uppermost mold layer among the moldlayers 104.

In an example embodiment, a lower end portion of the second doped region140Ld may be positioned on a higher level than a bottom surface of theinsulating pattern 127. The second doped region 140Ld may be positionedon a higher level than a second uppermost mold layer among the moldlayers 104.

In an example embodiment, the first and second doped regions 140Ld and140Pd and the insulating structure 124 may include a first element dopedthrough the ion implantation process 148. The first element may be agroup-5 element in the periodic table, phosphorus (P) or arsenic (As),for example. The first and second doped regions 140Ld and 140Pd may haveN-type conductivity. In an example embodiment, in the insulatingstructure 124, a doping profile of the first element may have themaximum concentration at a first height Rp (in FIG. 7) formed from anupper surface of the semiconductor pattern 140 and an upper surface ofthe insulating structure 124. The first height Rp (in FIG. 7) may bepositioned between an upper surface and a lower surface of theintermediate insulating layer 118. Thus, the first element in theinsulating structure 124 may have the maximum concentration in theinsulating structure 124. A material of the intermediate insulatinglayer 118 in which the first element is doped in the maximumconcentration through the ion implantation process 148 (FIGS. 23A and23A) may have etch selectivity with the mold layers 104.

Referring to FIGS. 13 and 24, a first capping insulating layer 150 maybe formed on the insulating structure 124. Also, separation trenches 153penetrating the first capping insulating layer 150, the insulatingstructure 124, and the mold structure 106 may be formed. Side surfacesof the interlayer insulating layers 102, the mold layers 104, and theinsulating structure 124 may be exposed by the separation trenches 153.

Referring to FIGS. 13, 25A, and 25A, empty spaces 156 may be formed byselectivity removing the mold layers 104 using an etching process. Theinterlayer insulating layers 102, the lower insulating layer 115, theintermediate insulating layer 118, and the upper insulating layer 121may be formed of a material having etch selectivity with the mold layers104, and thus, while the mold layers 104 are removed, the interlayerinsulating layers 102, the lower insulating layer 115, the intermediateinsulating layer 118, and the upper insulating layer 121 may remain.

Referring to FIGS. 13, 26A, and 26B, gate layers 162 may be formed inthe empty spaces 156 (in FIGS. 25A and 25B). The gate layers 162 mayinclude one or a plurality of lower gate layers 162L, a plurality ofinterlayer gate layers 162M, and one or a plurality of upper gate layers162U, stacked in order. The gate layers 162 and the interlayerinsulating layers 102 may be included in a stack structure 165.

Separation structures 175 filling the separation trenches 153 may beformed. The forming the separation structures 175 may include forming aspacer layer 170 on side walls of the separation trenches 153, andforming a separation core pattern 173 filling the separation trenches153. A second capping insulating layer 178 may be formed on theseparation structures 175 and the first capping insulating layer 150.Contact holes 181 penetrating the first and second capping insulatinglayers 150 and 178 and the insulating structure 124 in order may beformed in the connection region 25 by performing an etching process. Thecontact holes 181 may expose the gate layers 162. By forming theintermediate insulating layer 118 using a material different frommaterials of the first and second capping insulating layers 150 and 178,the upper insulating layer 121, and the lower insulating layer 115, theintermediate insulating layer 118 may be prevented from changing toproperties vulnerable to etching as the intermediate insulating layer118 is doped with the first element. Thus, the defect in which gapsbetween the contact holes 181 are excessively decreased or the defect inwhich the contact holes 181 are connected to each other, caused byover-etching the intermediate insulating layer 118 doped with the firstelement, may be prevented during an etching process for forming thecontact holes 181.

Referring back to FIGS. 13, 14A, and 14D, gate contact plugs 184 fillingthe contact holes 181 may be formed. Also, bit-line contact plugs 187penetrating the first and second capping insulating layers 150 and 178and electrically connected to the pad portions 140P of the verticalstructure VS may be formed. Further, bit lines 190 may be formed on thebit line contact plug 187, and gate connection wiring lines 192 may beformed on the gate contact plugs 184.

In the description below, a modified example of a method ofmanufacturing a semiconductor device will be described with reference toFIG. 27 in accordance with an example embodiment. FIG. 27 is across-sectional diagram illustrating a region taken along line IV-IV′ inFIG. 13.

Referring to FIGS. 13 and 27, a mold structure 106 including interlayerinsulating layers 102 and mold layers 104, alternately stacked, may beformed on a lower structure 50, a first lower insulating layer 115 a andan intermediate insulating layer 118′ may be formed in order on the moldstructure 106, and the intermediate insulating layer 118′, the firstlower insulating layer 115 a, and the mold structure 106 may bepatterned, thereby forming a staircase structure. Accordingly, theinterlayer insulating layers 102 and the mold layers 104 of the moldstructure 106 may be alternately stacked in a memory cell array region20 and may be formed in a staircase structure in a connection region 25adjacent to the memory cell array region 20, and the first lowerinsulating layer 115 a and the intermediate insulating layer 118′ may beself-aligned. A second lower insulating layer 115 b′ having an uppersurface coplanar with an upper surface of the intermediate insulatinglayer 118′ may be formed. For example, the forming the second lowerinsulating layer 115 b′ may include forming an insulating layer on alower structure 50 having the first lower insulating layer 115 a, theintermediate insulating layer 118′, and the mold structure 106, andplanarizing the insulating layer until an upper surface of theintermediate insulating layer 118′ is exposed. The first and secondlower insulating layers 115 a and 115 b′ may be included in a lowerinsulating layer 115. The upper insulating layer 121 illustrated in theexamples in FIGS. 21A and 21B may be formed, and the process describedwith reference to FIGS. 22A to 26A may be performed. Thus, asemiconductor device including the insulating structure 124 (in FIG. 15)illustrated in the example in FIG. 15 may be manufactured.

In the description below, a modified example of a method ofmanufacturing a semiconductor device will be described with reference toFIGS. 28 and 29. FIGS. 28 and 29 are cross-sectional diagramsillustrating a region taken along line I-I′ in FIG. 13.

Referring to FIGS. 13 and 28, the method may further include formingbuffer layers 151 isolating the intermediate insulating layer 118 of atleast the insulating structure 124 before the forming the separationtrenches 153 described with reference to FIG. 24. For example, theforming the buffer layers 151 may include, after forming the firstcapping insulating layer 150 as in the example illustrated in FIG. 24,forming openings penetrating the first capping insulating layer 150, theupper insulating layer 121, and the intermediate insulating layer 118 inorder and exposing the first lower insulating layer 115 a, and fillingthe openings with buffer material layers. In an example embodiment, thebuffer layers 151 may be formed of a silicon oxide.

Referring to FIGS. 13 and 29, separation trenches 153 penetrating thebuffer layers 151, the first lower insulating layer 115 a, and the moldstructure 106 in order may be formed.

In the example embodiment, the buffer layers 151 may be formed in thepositioned in which the separation trenches 153 are formed, and each ofthe buffer layers 151 may have a width greater than a width of each ofthe separation trenches 153. The buffer layers 151 may be isolated fromeach other by the separation trenches 153, and the buffer layers 151separated by the separation trenches 153 and remaining may cover a sidesurface of the intermediate insulating layer 118.

The mold layers 104 described with reference to FIGS. 25A and 25B may beremoved by an etching process, and the empty spaces 156 (in FIGS. 25Aand 25B) may be formed. During removing the mold layers 104 through anetching process, the buffer layers 151 may protect the intermediateinsulating layer 118 from the etching process. When the buffer layers151 are formed as above, a material for forming the intermediateinsulating layer 118 may not be limited to any particular material andmay vary. For example, the intermediate insulating layer 118 may beformed of a silicon oxide or a silicon nitride.

The gate layers 162, the separation structures 175, and the secondcapping insulating layer 178 described with reference to FIGS. 26A and26B may be formed in order by performing the process described withreference to FIGS. 26A and 26B. Accordingly, a semiconductor devicedescribed with reference to FIG. 16 may be manufactured.

In the description below, another modified example of a method ofmanufacturing a semiconductor device will be described with reference toFIG. 30. FIG. 30 is cross-sectional diagrams illustrating a region takenalong line I-I′ in FIG. 13.

Referring to FIGS. 13 and 30, after forming the separation trenches 153illustrated in the example in FIG. 24, a buffer layer 154 covering anupper region of the insulating structure 124 and covering a side surfaceof the intermediate insulating layer 118 of the insulating structure 124exposed by the separation trenches 153 may be formed. The buffer layer154 may be formed using a deposition process of which step coverageproperties is not good. Accordingly, after the buffer layer 154, a sidesurface of the intermediate insulating layer 118 may be covered by thebuffer layer 154, but the mold layers 104 may be exposed by theseparation trenches 153.

The mold layers 104 described with reference to FIGS. 25A and 25B may beremoved by an etching process, and the empty spaces 156 (in FIGS. 25Aand 25B) may be formed. During removing the mold layers 104 through anetching process, the buffer layer 154 may protect the intermediateinsulating layer 118 from the etching process.

The gate layers 162 described with reference to FIGS. 26A and 26B may beformed by performing the process described with reference to FIGS. 26Aand 26B.

In an example embodiment, after forming the gate layers 162, the bufferlayer 154 may be removed, and the separation structures 175 and thesecond capping insulating layer 178 described with reference to FIGS.26A and 26B may be formed in order. Thus, a semiconductor devicedescribed with reference to FIGS. 13, and 14A to 14D may bemanufactured.

In another example, after forming the gate layers 162, while remainingthe buffer layer 154, the separation structures 175 and the secondcapping insulating layer 178 described with reference to FIGS. 26A and26B may be formed in order. Accordingly, a semiconductor devicedescribed with reference to FIG. 17 may be manufactured.

In the aforementioned example embodiments described with reference toFIGS. 1 to 30, by disposing the intermediate insulating layer 118surrounding the doped regions 140Ld and 140Pd of the vertical structureVS, defects occurring between the vertical structure VS positioned on ahigher level than the stack structure 165 may be prevented. For example,by the ion implantation process 148 (in FIGS. 23A and 23B) for formingthe doped regions 140Ld and 140Pd of the vertical structure VS asdescribed above, the insulating structure 124 may include the firstelement, and a projected range (Rp) may be formed in the intermediateinsulating layer 118 in the insulating structure 124. By configuring theinsulating structure 124 to include the lower insulating layer 115, theintermediate insulating layer 118, and the upper insulating layer 121stacked in order as described above, and by forming the intermediateinsulating layer 118 using a material different from materials of thelower and upper insulating layers 115 and 121, defects which may occurduring a semiconductor process may be prevented. For example, asdescribed in the aforementioned example embodiments with reference toFIGS. 25A and 25B, as a material of the intermediate insulating layer118 doped with the first element by the ion implantation process 148 (inFIGS. 23A and 23B) may have etch selectivity with the mold layers 104,during forming the empty spaces 156 (in FIGS. 25A and 25B) by removingthe mold layers 104, the intermediate insulating layer 118 doped withthe first element by the ion implantation process 148 (in FIGS. 23A and23B) may remain without being etched or damaged. Thus, the insulatingstructure 124 including the intermediate insulating layer 118 mayprevent defects occurring between the doped regions 140Ld and 140Pd ofthe vertical structure VS adjacent to each other.

In the aforementioned example embodiments, defects occurring during theetching process for forming the contact holes 181 (in FIGS. 26A and 26B)used for forming the gate contact plugs 184 electrically connected tothe gate layers 162 of the stack structure 165 may be prevented. Forexample, gaps between the gate contact plugs 184 may become narrow dueto high density, and during the etching process for forming the contactholes 181 (in FIGS. 26A and 26B), the intermediate insulating layer 118doped with the first element by the ion implantation process 148 (inFIGS. 23A and 23B) may remain without being etched or damaged. Thus, theinsulating structure 124 including the intermediate insulating layer 118may prevent defects such as electrical shorts, current leakage, and thelike, occurring between the gate contact plugs 184 formed in the contactholes 181 (in FIGS. 26A and 26B).

Therefore, according to the aforementioned example embodiments, asemiconductor device including the stack structure and the insulatingstructure stacked in order, and the vertical structures penetrating thestack structure and the insulating structure may be provided. Theinsulating structure may include a lower insulating layer, anintermediate insulating layer, and an upper insulating layer, stacked inorder. The intermediate insulating layer may prevent defects occurringbetween the vertical structures positioned on a higher level than thestack structure.

While the example embodiments have been shown and described above, itwill be apparent to those skilled in the art that modifications andvariations could be made without departing from the scope of the presentapplication as defined by the appended claims.

What is claimed is:
 1. A semiconductor device, comprising: a stackstructure; a lower structure, wherein the stack structure is disposed onthe lower structure; an insulating structure disposed on the stackstructure; a vertical structure extending in a direction perpendicularto an upper surface of the lower structure, wherein the verticalstructure comprises a side surface opposing the stack structure andopposing the insulating structure; and a contact plug on and contactingthe vertical structure, wherein at least a portion of the stackstructure includes interlayer insulating layers and gate layers, whereinthe interlayer insulating layers and the gate layers are alternatelystacked, wherein the insulating structure includes a lower insulatinglayer, an intermediate insulating layer, and an upper insulating layer,wherein the intermediate insulating layer is disposed on the lowerinsulating layer, wherein the upper insulating layer is disposed on theintermediate insulating layer, wherein a material of the intermediateinsulating layer is different from a material of the lower insulatinglayer and a material of the upper insulating layer, wherein theintermediate insulating layer exhibits etch selectivity with respect tothe upper insulating layer and the lower insulating layer, wherein thevertical structure includes a core pattern, a channel region on a sidesurface of the core pattern, and a pad portion on the core pattern, andwherein the contact plug contacts the pad portion.
 2. The semiconductordevice of claim 1, wherein the intermediate insulating layer comprises adopant, and wherein the dopant includes a group-5 element of theperiodic table.
 3. The semiconductor device of claim 1, wherein athickness of the intermediate insulating layer is greater than athickness of each of the interlayer insulating layers.
 4. Thesemiconductor device of claim 1, wherein a thickness of the intermediateinsulating layer is greater than a thickness of each of the gate layers.5. The semiconductor device of claim 1, wherein the stack structure isdisposed in a memory cell array region and extends, at least in part,into a connection region adjacent to the memory cell array region,wherein the gate layers comprise pad regions, wherein the pad regionsare arranged in a staircase form in the connection region, wherein thelower insulating layer includes a first lower insulating layer and asecond lower insulating layer, wherein the second lower insulating layeris disposed adjacent to the first lower insulating layer, wherein thegate layers comprise an uppermost gate layer, wherein the first lowerinsulating layer overlaps the uppermost gate layer, and wherein thesecond lower insulating layer overlaps the pad regions.
 6. Thesemiconductor device of claim 5, wherein a thickness of the first lowerinsulating layer is greater than a thickness of each of the interlayerinsulating layers.
 7. The semiconductor device of claim 5, wherein athickness of the first lower insulating layer is greater than athickness of each of the gate layers.
 8. The semiconductor device ofclaim 5, wherein the first lower insulating layer and the second lowerinsulating layer are disposed below the intermediate insulating layer.9. The semiconductor device of claim 5, wherein the intermediateinsulating layer is disposed between the first lower insulating layerand the upper insulating layer, and wherein the upper insulating layeris in contact with the second lower insulating layer.
 10. Thesemiconductor device of claim 1, wherein at least a portion of the padportion is positioned on a same level as at least a portion of theintermediate insulating layer.
 11. The semiconductor device of claim 1,wherein the intermediate insulating layer is positioned at a level lowerthan the pad portion.
 12. The semiconductor device of claim 1, whereinthe pad portion and the insulating structure include a first element,and wherein a doping concentration of the first element in theintermediate insulating layer is higher than a doping concentration ofthe first element in the upper and lower insulating layers.
 13. Thesemiconductor device of claim 1, wherein the pad portion includes adoped polysilicon.
 14. A semiconductor device, comprising: a stackstructure; a lower structure, wherein the stack structure is disposed onthe lower structure; an insulating structure disposed on the stackstructure; a vertical structure extending in a direction perpendicularto an upper surface of the lower structure, wherein the verticalstructure penetrates the stack structure and penetrates the insulatingstructure; a capping insulating layer, wherein the capping insulatinglayer is disposed on the insulating structure and on the verticalstructure; and a separation structure, wherein the separation structureextends in the direction perpendicular to the upper surface of the lowerstructure, and wherein the separation structure penetrates the stackstructure, penetrates the insulating structure, and penetrates thecapping insulating layer; and a contact plug penetrating through thecapping insulating layer and contacting the vertical structure, whereinthe insulating structure includes a lower insulating layer, anintermediate insulating layer, and an upper insulating layer, whereinthe intermediate insulating layer is disposed on the lower insulatinglayer, wherein the upper insulating layer is disposed on theintermediate insulating layer, wherein a material of the intermediateinsulating layer is different from a material of the lower insulatinglayer and a material of the upper insulating layer, wherein theintermediate insulating layer exhibits an etch selectivity with respectto the upper insulating layer, and wherein the vertical structureincludes a core pattern, a channel region on a side surface of the corepattern and a doped region on the core pattern.
 15. The semiconductordevice of claim 14, wherein at least a portion of the stack structureincludes gate layers and interlayer insulating layers, wherein theinterlayer insulating layers are disposed between the gate layers,wherein the material of the interlayer insulating layers is differentfrom a material of the interlayer insulating layers, wherein theintermediate insulating layer comprises a dopant, and wherein the dopantincludes a group-5 element of the periodic table.
 16. The semiconductordevice of claim 14, further comprising: a buffer layer disposed on thestack structure and disposed between the separation structure and theintermediate insulating layer.
 17. The semiconductor device of claim 14,wherein the contact plug contacts the doped region, wherein the dopedregion is formed of a polysilicon, wherein an upper end of the dopedregion is at a higher level than the intermediate insulating layer,wherein the core pattern includes an insulating material, and whereinthe channel region includes a semiconductor material.
 18. Asemiconductor device, comprising: a stack structure; a lower structure,wherein the stack structure is disposed on the lower structure; aninsulating structure disposed on the stack structure; a verticalstructure extending in a direction perpendicular to an upper surface ofthe lower structure, wherein the vertical structure penetrates the stackstructure and penetrates the insulating structure; a capping insulatinglayer, wherein the capping insulating layer is disposed on theinsulating structure and on the vertical structure; gate contact plugs,wherein the gate contact plugs penetrate the capping insulating layerand penetrate the insulating structure; and a bit line contact plugpenetrates the capping insulating layer and contacting the verticalstructure, wherein the insulating structure includes a lower insulatinglayer, an intermediate insulating layer, and an upper insulating layer,wherein the intermediate insulating layer is disposed on the lowerinsulating layer, wherein the upper insulating layer is disposed on theintermediate insulating layer, wherein a material of the intermediateinsulating layer is different from a material of the lower insulatinglayer and a material of the upper insulating layer, wherein theintermediate insulating layer exhibits an etch selectivity with respectto the upper insulating layer and the lower insulating layer, andwherein the vertical structure includes a core pattern, a channel regionon a side surface of the core pattern and a pad portion on the corepattern.
 19. The semiconductor device of claim 18, wherein the stackstructure includes intermediate insulating layers and gate layers,wherein the gate contact plugs are electrically connected to pad regionsof the gate layers, wherein the intermediate insulating layer comprisesa dopant, and wherein the dopant includes a group-5 element of theperiodic table.
 20. The semiconductor device of claim 18, wherein thebit line contact plug contacts the pad portion of the verticalstructure, wherein the pad portion includes a polysilicon, wherein anupper end of the pad portion is at a higher level than the intermediateinsulating layer, wherein the core pattern includes an insulatingmaterial, and wherein the channel region includes a semiconductormaterial.